Rotary drill bit



Patented Mar. 6, 1923.

Lamai 'I' .di IC MONROE W. CARROLL, OFiBEAUMONT, TEXAS.

ROTARY DRILL BIT.

Application led October 14, 1920. Serial No. 416,930.

T 0 all whom it may concern:

Be it. known that I. MONROE W. CARROLL, a citizen of the Uni-ted States, and residing at Beaumont, Jefferson County, State 0f Texas, have invented certain new and useful Improvements Rotary Drill Bits, of which the following is a specific-ation.

This invention relates to rotary drill bits used` in sinking wells, particularly oil wells, in which the well shaft is projected downwardly through strataof various kinds and consistencies such as sand, loam and clay, water under pressure being forced downwardly by a hydraulic pump through the interior of the drill pipe. through the drill, and then passing upwardly around the drill pipe to the surface of the ground, carrying with it the cuttings which have been loosened by the cutting blades of the drill.

In drilling operations considerable diiiculty has been encountered in keeping the Water orifices in the drill free from obstructions. as particles of pump packing, trash and hose lining pass downwardly with the water 4being pumped and often clog t-he water orifices. It is an object of the present invention to provide means for preventing the clogging` of these orifices,` and this is accomplished by the addition of a straining dcvice so positioned at the lower end of the drill pipe that no particles of matter can pass into the drill, the straining device itself being of such capacity that it cannot become clogged.

Another cause of delay and vexation in drilling operations is due to the fact that when the hydraulic pumpat the top of the shaft is shut down sand and other material tends to force its way back lthrough the water orifices and into the drill pipe. A feature of this invention resides in the provision of means for preventing this inrush of water and foreign material, an automatic valve. being provided forv this purpose. It is further found that breakage of the drill pipe often occ-urs in its lowermost section, that is, the section immediately behind the drill, and that upon Withdrawal of the drill pipe the drill is left at the bottom of the well. My invention further contemplates means whereby the drill may be withdrawn with the main portion of the drill pipe even when the lowermost section of the drlll pipe has been broken. I

The 'invention will be fully disclosed in the followingV description when taken in connection with the accompanying drawings in which: v

Fig. 1 is a longitudinal section through the lower end of a drill pipe showing the improved drill secured thereto;

Fig. 2 is a side elevation of the drill bit partly broken awayto show the automatic valve;

Fig. 3 is a section on the line 3-3 of Figure l;

Fig. 4 is a section Figure 1; and

Fig. 5 is a view similar to Figure 2 showing a modified form of valve.

The drill pipe is in sections, two of which 10 and 11, are illustrated in the drawings, the section 11 being the lowermost section of the pipe, to which the bit is Secured. The adjacent ends of the sections are externally screw threaded and are screwed into the sleeve 12 which connects them, a spare being left between the adjacent ends of the pipe sections in which is positioned a. ring 13 having threaded engagement with the sleeve 12. The drill bit is indica-ted at 14. this bit having a hollow shank 15 exteriorly threaded to receive a sleeve 16 for connection to the lower lpipe section 11 and interiorly threaded to.receive a short tube 17 provided atits lower end with an annular valve seat 18. A coupling 19 has threaded engagement with the short tube 17 and with an elongated strainer'QO which extends upwardly above the ring 13 and has secured on the line 4 4 of to its upper end a cap 21 provided Withlugs 22 b v means of which it is centrally spaced within the pipe section 10.

The. shank of the. drill bit below the tube 17 is hollowed out to provide a chamber 23 for a ball valve 24 which may be of-any suitable material but preferably of metal and hollow so that it will float. The: charnber 23 has water outlet orifices 25 at its lower end to permit the outiow of water on either side of the drill bit or cutting blade.

In the operation of t-he drill it is constant y rotated by power mechanism 'at the top vof the. well sha-ft and water is forced downwardly through the interior of the drill pipe by a hydraulic pump, the Water passing through t-he holes in the st-rainer 20 and downwardly through the tube 17, forcing the Hoa-t yalve 24 from its seat and passing outwardly through orifices 25. It then passes upwardly around the drill pipe carrymg with 1t sand, clay, etc, loosely by the cutting blade. The strainer prevents foreign matter, such as pump packing, hose lining, etc., from clogging up ythe orifices 25, the strainer being of such length and having such capacity that it need only be cleaned'at long intervals. Whenever the hydraulic. power mechanism is shut down and the pressure within the drill pipe falls olf an)v external pressure of Huid at /the lower end of the drill will serve to raise the valve 24 and prevent the entrance of such fluid and sand and other foreign matter into the interior of the drill and drill pipe.

In case the lower section 11 of the drill pipe is broken in the drilling operation the drill is not lost inasmuch as it is connected to the next section 10 by means of the strainer tube 20 and cap 21, the diameter of the cap 21 across its'flanges 22 being larger than the inner diameter of the ring 13. When the main portion of the pipe is raised therefore the lugs 22 Will rest on the ring 13 and the drillwill be removed from the Well. 1

If desireda solid ball valve 24 ma)v be used instead of the hollow valve illustrated in Figure 1 and a spring 27 used to normally press this valveagainst its valve seat, this modification being illustrated in Figure 5.

Various changes may be made in the design and arrangement of the` component parts of the invention which is therefore not limited in its scope to the exact forms disclosed.

Having thus described my invention what I claim as new and desire to sec-ure by Letters Patent is 1. A drill bit having a passage therethrough for fluid under pressure, said passage having an enlarged portion or chamber Y ythe obstruction in the passage and the valve seat and adapted to move upwardly against the valve seat to prevent the flow of Huid through said passage in an upward direction.

3. The combination With a sectional drill pipe, of a drill bit secured to the end section thereof and having a portion constituting strainer extending through said end section and into the adjacent sec-tion, and a ring positioned between the ends of said sections for engaging said portion when the end section is broken, for the purpose set forth.

4. The combination with a sectional drill pipe, of a drill bit secured to the end section thereof and having a portion constituting a strainer extending through said end section and into the adjacent sec-tion, the end of said portion being enlarged, and a ring of ysmaller inside diameter than the diameter of the enlarged end of said portion secured between the ends of said sections for engaging said portion when the end section is broken, for the purpose set forth.

In testimonf/[Whereof affix mv siganture.

ONROE W. CRROLL. 

